The existing diagnostic systems of some spheres of plants' activities have been analyzed and conditions, problems and difficulties of their usage determined. The necessity of formation of the universal matrix model of aim's choice of the representative indicators of the machine-building plants activity has been substantiated and main conceptual principles of its construction and usage determined. These indicators have been systematized and classified with regard to the industrial, technological-property, cadre, social, financial, material-supply, marketing, time, general economical, specific and foreign activity, characteristics of product and capitalization matters. The partial and concrete aims of diagnostics of different subjects of the analysis have been determined.